4º A - NATURAL SCIENCE: SIMPLE MACHINES

4ºA

SIMPLE MACHINES

Simple machines

LEVERS

A lever makes it easier to move an object.

It is a rigid bar with a pivot point. This is the point where the lever turns. The object we need to move exert a force. This is called the load. The person using the lever applies a force which is called the effort.

PULLEY

A pulley uses a wheel, an axle and a rope.

The axle passes through the centre of the wheel. There is a groove on the outside of the wheel and a rope runs around it.

RAMPS

An inclined plane is a ramp used to lift and to lower objects.

The longer the ramp, the less inclined it is. This means you move the load a bigger distance but you need less effort. It also means you can move a bigger load.

SCREW

A screw is an inclined plane wrapped around a pole. Some slides are screws.

Slide

WEDGE

A wedge is two inclined planes back to back. An axe is a wedge.